The present invention relates to processes for making non-aqueous liquid laundry detergent products which contain an organic anhydrous solvent, an anionic sulfonated surfactant as well as other conventional detergent composition adjuvants and which are in the form of a Newtonian liquid, as well as the drying of (removing water from) detergent ingredients, especially polymers, surfactants and/or solvents, more especially polymers and surfactants for use in detergent compositions. In addition to the above, the present invention also provides a means of converting Newtonian liquids into non-Newtonian liquids and non-Newtonian liquids into Newtonian liquids.
Liquid laundry detergent products offer a number of advantages over dry, powdered or particulate laundry detergent products. Liquid laundry detergent products are readily measurable, speedily dissolved in wash water, non-dusting, are capable of being easily applied in concentrated solutions or dispersions to soiled areas on garments to be laundered and usually occupy less storage space than granular products. Additionally, liquid laundry detergents may have incorporated into their formulations materials which would deteriorate in the drying operations employed in the manufacture of particulate or granular laundry detergent products. Because liquid laundry detergents are usually considered to be more convenient to use than granular laundry detergents, they have found substantial favor with consumers.
Although liquid laundry detergents have a number of advantages over granular laundry detergent products, there are also disadvantages entailed in using them as well. In particular, laundry detergent composition components which may be compatible with each other in granular products may tend to interact or react with each other in a liquid, and especially in an aqueous liquid, environment. Components such as surfactants, perfumes, brighteners and non-aqueous solvents can be especially difficult to incorporate into liquid laundry detergent products with an acceptable degree of compositional stability. Poor compositional stability may cause the detergent composition to be prematurely reacted into the wash liquor as well as create an ineffective, heterogeneous detergent composition during storage.
One approach for enhancing the chemical compatibility and stability of liquid laundry detergent products has been to formulate non-aqueous (or anhydrous) liquid laundry detergent compositions. Generally, the chemical stability of the components of a non-aqueous liquid laundry detergent composition increases as the amount of water in the laundry detergent composition decreases. Moreover, by minimizing the amount of water in a liquid laundry detergent composition, one can maximize the surfactant activity of the composition. Non-aqueous liquid laundry detergent compositions have been disclosed in Hepworth et al., U.S. Pat. No. 4,615,820, Issued Oct. 17, 1986; Schultz et al., U.S. Pat. No. 4,929,380, Issued May 29, 1990; Schultz et al., U.S. Pat. No. 5,008,031, Issued Apr. 16, 1991; Elder et al., EP-A-030,096, Published Jun. 10, 1981; Hall et al., WO 92/09678, Published Jun. 11, 1992 and Sanderson et al., EP-A-565,017, Published Oct. 13, 1993.
But non-aqueous liquid laundry detergents come with their own set of disadvantages and problems. The desirable advantage of having excellent compositional stability, may mean simultaneously that the non-aqueous liquid laundry detergent will have poor solubility and dispersion properties in the wash liquor inside an automatic clothes washer. Also non-aqueous liquids typically have awkward rheological properties, displaying a tendency known as xe2x80x9cshear thickeningxe2x80x9d, where the viscosity of the paste or liquid increases with an increasing shear rate making the paste difficult to pump, store and transport. Moreover, non-aqueous liquid laundry detergent compositions are difficult and expensive to manufacture. A drying step requiring prolonged heating and stirring is necessary to eliminate the water, but not only is it difficult to consistently achieve the proper heating and stirring conditions in a manufacturing setting, but such drying operations may also have the effect of decomposing or evaporating individual components of the detergent composition. The resulting difficulty and expense involved with working with such fluids has greatly reduced their utilization as laundry detergent compositions.
Given the foregoing, there is clearly a continuing need to identify and provide processes for preparing non-aqueous liquid laundry detergent products that have a high degree of chemical and compositional stability, contain the essential components of a liquid laundry detergent composition, have a high surfactant activity and are readily soluble in a wash liquor. In addition, such processes should be easily replicated at multiple production sites and should produce liquid laundry detergent products that can be easily pumped, stored and transported.
A process for preparing a solvent-based surfactant paste comprising the steps of:
A) forming an aqueous surfactant mixture by blending, by weight of the mixture:
(a) from about 5% to about 85% of an anionic sulfonated surfactant;
(b) from about 15% to about 95% of an organic solvent;
(c) from about 0.001% to about 40% of a chelant;
wherein the aqueous surfactant mixture has a water content of about 5% to 80% by weight of the aqueous surfactant mixture and the aqueous surfactant mixture is a non-Newtonian fluid;
B) drying the aqueous surfactant mixture under vacuum to form the solvent-based surfactant paste having a water content of less than about 1% and which is in the form of a Newtonian fluid having a substantially constant viscosity within the range of 100 cp to 100000 cp when measured at a temperature of 25xc2x0 C. and within the shear rate range of from 1 sxe2x88x921 to 1000 sxe2x88x921.
The process of above wherein the aqueous surfactant mixture may further comprise from about 0.001% to about 40% of other additives selected from the group comprising bleach, bleach activator, buffers, builders, enzymes, whiteners, rheology modifiers, polymers and copolymers, wherein the other additives are provided in the form of an aqueous solution.
The process of above wherein the aqueous surfactant mixture is dried in an evaporative column.
The process of above wherein the step of forming an aqueous surfactant mixture includes blending from about 0.001% to about 40% of an ethoxylated hexamethylene diamine quaternary ammonium compound.
The process of above wherein the step of forming an aqueous surfactant mixture includes blending from about 0.001% to about 40% of other additives selected from the group comprising bleach, bleach activator, builder, enzymes, nonionic surfactants, whiteners and polymers.
The process of above wherein the organic solvent is selected from a group consisting of alkylene glycols, diethyl- and dipropylene glycol monobutyl ethers, glycol monobutyl ether, monoethylethers, monomethylethers, monopropylethers and monobutylethers of propoxy propanol, polyethlene glycols having a molecular weight of at least about 150, methyl acetate, methyl propoinate, methyl octanoate, methyl dodecanoate and mixtures thereof.
The process of above wherein the chelant is selected from a group consisting of amino carboxylates, phosphonates, amino phosponates, polyfunctionally-substituted aromatic chelating agents and mixtures thereof.
A process for preparing a solvent-based surfactant paste comprising the steps of:
A) forming a neutralized mixture by a continuous neutralization loop, the neutralized mixture has a composition comprising:
(a) an acid form of an anionic sulfonated surfactant and a base present in a molar ratio of from about 1:1 to about 9:1;
(b) an organic solvent; and
(c) a chelant;
wherein the neutralized mixture has a water content of from about 5% to about 50% by weight of the neutralized mixture and is a non-Newtonian fluid.
B) recirculating a first portion of the neutralized mixture;
C) removing a second portion of the neutralized mixture from the continuous neutralization loop;
D) drying the second portion of the neutralized mixture under vacuum to form the solvent-based surfactant paste having a water content of from about 0.2% to about 10% and which is in the form of a Newtonian fluid having a substantially constant viscosity within the range of 100 cP to 100000 cP when measured at a temperature of 25xc2x0 C. and within the shear rate range of from 1 sxe2x88x921 to 1000 sxe2x88x921.
The process of above where the neutralized mixture further comprises other additives selected from the group comprising bleach, bleach activator, buffers, builders, enzymes, nonionic surfactants, whiteners, rheology modifiers, polymers and copolymers, wherein the other additives are provided in the form of an aqueous solution which has a water content of from about 5% to about 50% by weight of the neutralized mixture.
The process of above wherein the second portion of neutralized mixture is dried in an evaporative column.
The process of above wherein the acid form of an anionic surfactant is selected from a group consisting of linear alkyl benzene sulphonic acid, alkyl ethoxy sulphonic acid, alkyl polyalkylate sulphonic acid, tallow alkyl sulphonic acid and alkyl sulphonic acid.
The process of above wherein the organic solvent is selected from a group consisting of alkylene glycols, diethyl- and dipropylene glycol monobutyl ethers, glycol monobutyl ether, monoethyl-, monomethyl-, monopropyl- and monobutylethers of propoxy propanol and mixtures there of, polyethlene glycols having a molecular weight of at least about 150, methyl acetate, methyl propoinate, methyl octanoate and methyl dodecanoato.
The process of above wherein the chelant is selected from a group consisting of amino carboxylates, phosphonates, amino phosponates, polyfunctionally-substituted aromatic chelating agents and mixtures thereof.
The process of above wherein after step C additional organic solvent is added to the neutralized mixture, so that after the addition of the additional organic solvent the neutralized mixture has a water content of from about 5% to about 50% by weight of the neutralized mixture.
The process of above wherein after step C additional chelant is added to the neutralized mixture, so that after the addition of the additional chelant the neutralized mixture has a water content of from about 5% to about 50% by weight of the neutralized mixture.
A process for drying detergent ingredients comprising the steps of:
A) forming an aqueous detergent ingredient mixture by blending, by weight of the mixture wherein the aqueous detergent ingredient mixture has a water content of about 5% to 80% by weight of the aqueous detergent ingredient mixture;
B) drying the aqueous detergent ingredient mixture using an Agitated Thin Film Evaporator.
A process for converting Newtonian liquids into non-Newtonian liquids comprising the steps of:
A) forming an aqueous Newtonian liquid mixture; and
B) drying said mixture using an Agitated Thin Film Evaporator (ATFE) such that a non-Newtonian liquid is produced.
A process for converting non-Newtonian liquids into Newtonian liquids comprising the steps of:
A) forming an aqueous non-Newtonian liquid mixture; and
B) drying said mixture using an Agitated Thin Film Evaporator (ATFE) such that a Newtonian liquid is produced.
A process for preparing anhydrous agglomerates comprising the steps of:
A) producing a binder;
B) drying said binder using an Agitated Thin Film Evaporator; and
C) combining said dried binder with powders such that an agglomerate is produced.
It is a benefit of the present invention is to provide a process which produces a liquid laundry detergent composition that is easy to handle in bulk. Since it does not display shear thickening, but is in fact a Newtonian fluid over a broad range of shear rates, it is considerably easier to store, pump and transport when compared with other non-aqueous liquids.
An additional benefit of the present invention is a process for drying (removing water from) detergent ingredients, especially polymers, surfactants and/or solvents, more especially polymers and surfactants for use in detergent compositions. Such a process preferably comprises the steps of forming an aqueous detergent ingredient mixture and drying said mixture using an Agitated Thin Film Evaporator (ATFE).
Yet a further benefit of the present invention is a process for converting Newtonian liquids into non-Newtonian liquids and non-Newtonian liquids into Newtonian liquids. Such a process preferably comprises the steps of forming an aqueous Newtonian liquid mixture and drying said mixture using an Agitated Thin Film Evaporator (ATFE) such that a non-Newtonian liquid is produced. Alternatively, the process preferably comprises the steps of forming an aqueous non-Newtonian liquid mixture and drying said mixture using an Agitated Thin Film Evaporator (ATFE) such that a Newtonian liquid is produced.
An additional benefit of the present invention is to provide a process for preparing non-aqueous liquid laundry detergent products which have excellent chemical and compositional stability as well as outstanding fabric laundering performance characteristics. In addition the processes produce non-aqueous liquid laundry detergent products that are readily soluble in a wash liquor.
A further benefit is to provide a process for combining aqueous solutions of detergent components and then drying them together to produce a liquid mixture with a water level lower than what could be achieved by combining non-aqueous solutions of the components.
Still yet a further benefit of the present invention is to provide a process for preparing anhydrous agglomerates, preferably comprising organic solvents, surfactants, other detergent adjunct ingredients and/or combinations thereof, wherein the process comprises the step of producing a binder, preferably an anhydrous binder, which is preferably a highly viscous, non-Newtonian solvent based mixture of preferably one or more organic solvents, one or more surfactants, one or more chelants and/or one or more polymers, preferably anhydrous liquid polymers. In a preferred embodiment, the anhydrous binder is formed by mixing an anionic material, preferably an anionic surfactant, more preferably linear alkylbenzene sulfonate, with a cationic material, preferably a cationic anhydrous liquid polymer. Preferably the mixture is made in an aqueous phase in the presence of an organic solvent and then further dried using a drying process described herein, preferably using an Agitated Thin Film Evaporator (ATFE), to produce an anhydrous binder. The anhydrous binder can then be combined with powders, such as citrates, carbonates, silicates, and the like, to form anhydrous agglomerates. Such a process provides anhydrous agglomerates that do not require a further drying step after the agglomeration step. These anhydrous agglomerates are useful in product forms including, but not limited to, liquid detergent products, especially anhydrous liquid detergent products, and in detergent tablet products.
Even yet another preferred aspect of the present invention, a process for making and/or drying surfactants or combinations of surfactants and/or other detergent adjunct ingredients such as chelants, builders, buffers, rheology modifiers and the like. Such a process comprises preparing a mixture of surfactants and/or other detergent adjuncts in an aqueous medium or a combination of aqueous and solvent media. This preparation step may be achieved by mixing these materials in their neutralized aqueous and/or powder form or by co-neutralizing them in the presence or absence of a solvent batchwise or continuously in a dominant bath neutralization loop such as a Chemithon, Ballestra or Manro unit. The drying step comprises feeding the prepared mixture into a drying device or equipment which is a batch or continuous drying equipment. An example of batch drying equipment is a combination tank preferably agitated, which can be heated under vacuum. The tank is operated at suitable vacuum and temperature such that water is stripped from the mixture. An example of a continuous drying equipment is an Agitated Thin Film Evaporator (ATFE). A suitable ATFE is commercially available from LCI Corporation. This process is also suitable for expanding hollow microspheres, such as EXPANCEL(copyright) microspheres. As the hollow microspheres pass through the drying equipment (ATFE) the microspheres expand because the temperature of the ATFE is above the expansion temperature of the microspheres.
Thus the compositions produced according to the processes disclosed herein the above benefits which are novel to non-aqueous compositions and yet these process produce compositions that are typical of a non-aqueous liquid laundry detergent composition, viz. a high surfactant activity and excellent additive stability.
In one embodiment, the process comprises a formation step in which an aqueous surfactant mixture is formed by mixing an anionic sulfonated surfactant, an organic solvent or carrier and a chelant and a drying step in which the aqueous surfactant mixture under vacuum to form a solvent-based surfactant paste containing less than about one percent, by weight, of water. This process may be modified such that an individual ingredient can be processed, thereby producing a xe2x80x9cdriedxe2x80x9d ingredient. For example, an anionic sulfonated surfactant could be dried via the drying step such that the anionic sulfonated surfactant final product contains less than about 1% by weight of water.
The aqueous surfactant mixture in the formation step contains from about 5% to about 85% of an anionic sulfonated surfactant, from about 15% to about 95% of an organic solvent, from about 0.001% to about 40% of a chelant and at least about 15% of water by weight of the aqueous surfactant mixture. The aqueous surfactant mixture in the formation step is a non-Newtonian fluid.
The solvent-based surfactant paste produced by the drying step is a Newtonian fluid and having a substantially constant viscosity within the range of 100 cp to 100000 cp when measured at a temperature of 25xc2x0 C. and within the shear rate range of from 1 sxe2x88x921 to 1000 sxe2x88x921.
A preferred embodiment also includes mixing into the aqueous surfactant mixture other additives such as buffers, builders, nonionic surfactants, polymers and copolymers and other additives.
The present invention may also be practiced in a second aspect. This embodiment comprises a neutralization step in which a neutralized mixture is formed by a continuous neutralization loop. This neutralized mixture contains an acid form of an anionic surfactant, a base, an organic solvent, and a chelant. The neutralized mixture has a water content of at least about 5% by weight of the neutralized mixture and is a non-Newtonian fluid. The molar ratio of the acid form of the anionic surfactant to the base is from about 1:1 to about 9:1.
In a subsequent step, a first portion of the neutralized mixture is then removed from the continuous neutralization loop and dried under vacuum to form a solvent-based surfactant paste having a water content of from about 0.2% to about 10% and which is in the form of a Newtonian fluid having a substantially constant viscosity within the range of 100 cp to 100000 cp when measured at a temperature of 25xc2x0 C. and within the shear rate range of from 1 sxe2x88x921 to 1000 sxe2x88x921 while a second portion of the neutralized mixture is recirculated in the continuous neutralization loop.
If so desired, additional chelant and solvent may be added to the neutralized mixture after the neutralized mixture is removed from the neutralization loop.
The present invention offers the advantage of preparing a surfactant paste with only a trace amount of water and yet can incorporate many of the ingredients desirable for use in a laundry detergent composition such as bleach, bleach activators, builders, enzymes, whiteners and other additives. By minimizing the amount of water in the surfactant pastes or mixtures, one may maximize the activity of the surfactant paste. Furthermore, the present invention allows the manufacture of a high-active surfactant paste or mixtures in the form of a Newtonian Fluid that has a low viscosity and so is capable of being transported, stored and handled with ease.
All percentages, ratios and proportions herein are by weight, unless otherwise specified. All documents cited are, in relevant part, incorporated herein by reference.